Give the blame where it is due everyone is overlooking the fact the game is always about self improvement.
Fuck the guy if he was good enough to steal your girl...there was holes in your game i'm sorry to say it but tighten up.
As a fellow community member i mean this in the most enlightening way, progress towards a goal you were dancing she was getting all touchy feely and you didn't capatalize man!
If im running dance floor game (and i absolutley love to) i give them one song now during the duration of this song i will be dancing very sexually.
After one song I k close re-isolate make out and bounce or # close and time constraint it shouldn't take you multiple songs to escalate
Let the guy do his thing the best response is always a cocky funny one. My buddies always try to steal my sets you should of tried something along the lines of
tell her "You know what i like about you, you're cool and honest ( qualification) , so im going to be honest with you.....(pause for effect) my buddy over there said you were the easiest girl in the club and he said you are all over everyone so he said he could easily fuck you tonight." The reason i didnt tell you at first is because i thought you would freak out and make a scene like every other girl... you're not like every other girl are you?( more qualification to seal the deal)
Or if you want to be less malicious " My buddy is always so playful before he ties up young women in his cellar"

Or "He Really likes dancing with girls after he puts the special herpes ointment on"
Anything to add value to you and make him look like your pet